Casing bridging plug



2 Sheets-Sheet l Dec. 14, 1954 c. WARE CASING BRIDGING PLUG Filed Sept.16. 1950- :Lcq. :L.

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C. WARE CASING BRIDGING PLUG 2 Sheets-Sheet 2 Em. a A

INVENTOR.'

660d Ware ATTORNEY United States Patent CASING BRIDGING PLUG Cecil Ware,Houston, Tex.

Application September 16, 1950, Serial No. 185,178

7 Claims. (Cl. 166-124) This invention relates to a casing bridging plugfor oil wells and more particularly to a bridging plug having improvedpacker means and embodying an improved arrangement of parts wherebysetting of the device in the well is facilitated.

The invention has for an important object the provision of a bridg ngplug haying upwardly and downwardly opening oppositely disposed cup-typepacking elements, and including releasable means for preventing damageto the downwardly opening element caused by encountering irregularitiesin the well casing while the plug is being moved in the casing. Anotherobject of the invention is to provide a bridgmg plug embodying means formaintaining the plug in open condition to allow circulation of fluidtherethrough, which means is operable upon setting of the plug anddisconnection of the circulating tube therefrom to close the plugagainst upward circulation of fluid therethrough.

The invention may best be understood from the following detaileddescription of a preferred embodiment of the same when considered withthe annexed drawings in which Figure l is an elevational view partly incross-section showing the upper end of the bridging plug and therelationship of the parts thereof when the plug is inserted in thecasing;

Figure l-A is an elevational view partly in cross-section showing thelower end of the bridging plug under the same conditions as in Figure 1;

Figure 2 is a view similar to that of Figure 1, showing the relationshipof the parts after the bridging plug has been set in the well casing;

Figure 2-.-A is a view similar to Figure 1-A, showing the bridging plugin set condition in the well casing; and

Figure 3 is an elevational view partly in cross section, showing aportion of the lower end of the bridging plug in closed condition afterdisconnection and removal of the circulating tube therefrom.

As shown in the drawings, wherein like reference numerals indicate likeparts throughout the several views, the bridging plug has a tubularmandrel 10, provided at its upper end with external threads by which themandrel is attached to a safety coupling device comprising a lowermember 12 and an upper member 14.

The lower coupling member 12 is threaded internally at its lower end forthe attachment of the mandrel thereto and is externally threaded at itsupper end for attachment to the upper coupling member 14. The uppercoupling member 14 is internally threaded for attachment to the lowercoupling member, and for attachment at its upper end to the end of atubular string of pipe indicated at 16 in Figure 1. Mediate its ends thelower coupling member may have an exterior groove 18, for the receptionof packing, such as an O-ring, to form a fluid seal with the innersurface of the upper coupling member. The upper coupling member isprovided with an internal perforated web 20, having a central threadedopening for the attachment thereto of a rod 22, for a purpose later tobe made apparent. The upper coupling member 14 has a cylindrical lowerend portion which fits over the lower coupling member to form a fluidseal therewith by means of the groove 18 having an O-ring as previouslydescribed.

The above described coupling arrangement is intended to permitdisconnection of the bridging plug from the tubular string should thisbe necessary.

- A slip-expander or cone 24 surrounds the upper end 2,696,885 PatentedDec. 14, 1954 portion of the mandrel 10, and is formed with a tapernglower portion 26. At its upper end the slip expander 1s externallythreaded for the attachment thereto of a top bushing 28 A cup ring 30surrounds the slip-expander 24, which ring may be internally grooved, asat 32 to receive packing such as an O-ring to form a fluid seal betweenthe expander and the ring. The ring 30 is held between the top bushing28 and a top shoe 34 which surrounds the expander and engages anexternal shoulder 36 thereon.

An upwardly-opening cup-type packing element 38 surrounds the cup ring30, and the shoe 34 has a downwardly and inwardly tapering wall 40 whichengages the lower portion of the packing element 38 to retain the sametightly in engagement with the cup ring. The cup ring may be molded intothe resilient material of the packing element, so that thepacking'element may be placed in position on the expander by removingthe top bushing 28, sllpping the shoe 34 and then the ring and packingelement on the expander and then replacing the top bushing.

There is a slip cage 42 surrounding the mandrel 10, which cage isexternally threaded at its lower end for the attachment thereto of theinternally threaded upper end of a bottom bushing 44. Slips comprisingslip blocks 46, are disposed in openings at spaced intervals about theperiphery of the slip cage, for lateral movement in the cage. The slipblocks have downwardly and inwardly tapered inner surfaces forengagement with a corresponding surface on the expander, whereby theslip blocks may be moved outwardly of the cage. Each of the slip blockshas a longitudinal groove 48 therein, which may be under cut to receivethe head of a screw 50, by which the slip block is moveably attached tothe expander.

There is a ring 43 fixed on the mandrel 10 and engageable with aninternal shoulder 45 on the expander 24 to prevent the downward movementof the expander and premature setting of the slips in engagement withthe casing before the plug has been positioned in the desired location,and the mandrel and ring moved to the position seen in Figures 2 and2-A.

An internal groove 47 is also provided in the slip cage for thereception of an O-ring or the like with which the ring 43 has sealingcontact when in the position shown in Figure 2-A.

Slip inserts 52 are carried by the slip blocks, which inserts areoutwardly toothed for engagement with the well casing, indicated at 54,to anchor the bridging plug in the well. Friction blocks 55, ofconventional construction are also carried by the slip cage, andprovided with means, not shown, whereby the friction blocks are urgedoutwardly into engagement with the well casing to resist turning of thebridging plug in the casing.

The slip cage 42 has a thickened portion 56, mediate its ends providinga downwardly facing shoulder 58. A cup ring 60 similar to the'cup ring30, previously described, surrounds the slip cage, and this ring mayalso be internally grooved, as at 62 to receive packing such as anO-ring to form a fluid seal between the ring and the cage.

About the slip cage, in engagement with the shoulder 58 thereof, thereis a bottom shoe 64, similar to the shoe 34, and the ring 60 is heldbetween this shoe and the upper end of the bottom bushing 44. Adownwardly opening cup-type packing element 66 surrounds the cup ring 60and is retained thereon by the aid of the bottom shoe 64 in the samemanner as in the case of the packing element 38 on the ring 30,previously described.

At its lower end the slip cage 46 has a downwardly and outwardly taperedinner wall portion 68 and the bottom bushing 44 is provided with aninternal upwardly facing shoulder 70 forming a seat for an outwardlytapering locking nut 72 seated thereon inside the cage. The locking nuthas inwardly directed internal teeth 74 thereon which mesh with opposedexternal teeth 76 formed on the tubular mandrel 10, for a purpose laterto be made apparent.

Internal threads 78 are also provided on the lower end of thebottonnbushing 44 which intermesh with external threads 80.near thelower end of the tubular mandrel,

in the condition of the plug shown in Figures 1 and l-A.

A valve cage 82 is attached to the lower end of the tubular mandrel by asuitable threaded connection, and carries therein a valve 84, which hasan external annular seat engaging portion 86, adapted to seat on a valveseat 88 formed on the lower end of the mandrel. External annular grooves90 may be provided in the valve 84 for the reception of packing such asO-rings to form a fluid seal between the tubular mandrel 10 and thevalve. An exterior, downwardly-widening,tapered groove 92 is also formedin the valve 84, in which an upwardly tapered valve lock is seated,which has external teeth 94 serving to grippingly engage the inside ofthe valve cage to resist downward movement of the valve therein, whenthe valve is in closed position, as best seen in Figure 3.

A removable plug 96 may be provided closing the lower end of the valvecage, for convenience in assembling the parts, and to form a seat for aresilient member 98 in the form of a coil spring which enters a recess1100 in the bottom of the valve, and is effective to urge the valvetoward its closed position. Slotted openings 102 may also be formed inthe valve cage to permit passage of fluid therethrough. About the valvecage, and operatively engageable with an external shoulder 104 thereon,there is a cup protector 106, which is open at its upper end to receivethe lower end of the packing element, when the plug is in the conditionshown in Figures 1 and 1A. The cup protector serves to depress the lowerportion of the packing element 66 toward the mandrel 10, so that thepacking element will not be damaged by encountering irregularities inthe casing when the plug is inserted therein. The cup protector has aninwardly directed portion 108, which is engaged by the shoulder 104 ofthe valve cage upon downward movement thereof to move the protectordownwardly and release the packing element 66. Openings 110 are alsoformed in the cup protector for the passage of fluid therethrou'gh.

In the condition of the bridging plug shown in Figures 1 and 1A, the rod22 extends downwardly from the improved bridging plug is provided, whichcan be readily inserted in the well, is capable of being easilymanipulated to perform a number of diiffefrent functions, and by whichvarious well cementing operations can be conveniently carried out.

The invention has been disclosed in connection with one preferredembodiment of the same but it will be understood that this is intendedby way of example only, and various modifications can be made in theconstruction and arrangement of the parts within the scope of theappended claims.

What is claimed is:

l. A bridging plug for wells comprising, a tubular member adapted to beconnected to a string of pipe for movement with said string, a slip cagearound the member and slidable longitudinally relative thereto,casing-engaging slips carried by the cage and movable into and out ofengagement with a surrounding well casing, a slip expander around themember and movable longitudinally of the cage to engage and expand theslips, releasable means connecting the cage to the member for movementtherewith, said member being rotatable in the cage to release saidconnecting means and being movable downwardly in the cage when releasedtherefrom, means on the cage safety coupling upper member 14 through themandrel 10 and engages the valve 84 in a recess 112 therein, pressingthe valve downwardly against the spring 98 to open position. The plug isinserted in the well in this condition, with the cup protector 106 overthe open end of the packing element 66, and the plug attached to thelower end of a tubular string of pipe 16.

When the plug has been lowered to the desired depth, circulation maytake place downwardly through the string 16 and through the plug,emerging through the openings 102 in the valve cage and openings 110 inthecup protector into the casing below the plug. Fluid may also passupwardly in the casing about the plug past the packing elements 66 and38.

The plug may be set in the well by rotating the tubular string touncouple the threads 80 of the mandrel 10 from the threads 78 of thebottom bushing 44, the friction blocks 55 holding the slip cage againstrotation. The mandrel may then be moved downwardly to engage the lowerend of the coupling member 12 with the expander '24, thereafter forcingthe expander downwardly and moving the slips into anchoring engagementwith the easing. Downward movement f the mandrel 10 also carries thevalve cage 82 downwardly engaging the shoulder 104 thereof with theinwardly directed portion 108 of the cup protector, and moving the cupprotector downwardly to release the packing element 66, as seen inFigure 2-A. Circulation of fluid upwardly in the casing is thenprevented by the packing element 66.

As the mandrel 10 moves downwardly the teeth 74 of the tapered lockingnut 72 slip past the teeth 76 of the mandrel, so that any upwardmovement of the mandrel will cause the nut to lock against the taperingwall 68 of the slip cage, and the tubular string may then be releasedfrom the plug by appropriate rotation to disconnect the I safetycoupling from the mandrel.

As best seen in Figure 3, upon removal of the tubular string from theplug, the rod 22 will be elevated with the string and the valve 84 willthen be seated, closing the mandrel 10 so that circulation through theplug can no longer take place. When the valve moves upwardly into seatedposition the valve lock is carried upwardly therewith and grips theinside of the valve cage to prevent subsequent unseating of the valve bypressure in the casing from above the plug.

From the above description of the structure and manner of use of theinvention it will be apparent that an frictionally engageable with thecasing to hold the cage stationary in the casing during such rotationand downward movement of the member, means on the member engageable withthe slip expander to move the expander downwardly with the member toexpand the slips into gripping engagement with the casing to anchor thecage in the casing, packing means carried by the expander and the cageand engageable with the casing to seal the casing against the flow offluid past the plug in either direction, a downwardly opening valvecarried by the member, means carried by the member and cooperable withthe valve and member to yieldingly move the valve toward a position toclose said member, and means on the valve engageable with the member tohold the valve in said closed position.

2. A bridging plug for wells comprising, a tubular member, couplingmeans releasably connecting the memher to a string of pipe for movementwith the string and releasable by rotation of the string relative to themember, a slip cage around the member and slidable longitudinallyrelative thereto, casing-engaging slips carried by the cage and movableinto and out of engagement with a surrounding well casing, a slipexpander around the member and movable longitudinally of the cage toengage and expand the slips, releasable means connecting the cage to themember for movement therewith, said member being rotatable in the cageto release said connecting means and being movable downwardly in thecage when released therefrom, means on the cage frictionally engageaolewith the casing to hold the cage stationary in the casing during suchrotation and downward movement of the member, means on the memberengageable with the slip expander to move the expander downwardly withthe member to expand the slips into gripping engagement with the casingto anchor the cage in the casing, packing means carried by the expanderand the cage and engageable with the casing to seal the casing againstthe flow of fluid past the plug in either direction, a downwardlyopening valve carried by the member, yieldable means carried by themember and cooperable with the valve and member to urge said valvetoward a position to close the member, means carried by the couplingmeans and engageable with the valve to hold the valve in open positionand means carried by the valve and engageable with the member uponclosing of the valve to retain the valve in closed position.

3. A bridging plug for wells comprising, a tubular member adapted to beconnected to a string of pipe for movement with said string, a slip cagearound the member and slidable longitudinally relative thereto,casing-engaging slips carried by the cage and movable into and out ofengagement with a surrounding well casing, a slip expander around themember engageable with the slips and movablerlongitudinally of the cageto expand the slips, releasable means connecting the cage to the memberfor movement therewith, said member being rotatable in the cage torelease said connecting means and being movable downwardly in the cagewhen released therefrom, means on the cage frictionally engageable withthe casing to hold the cage stationary in the casing during suchrotation and downward movement of the member, the slip expander to movethe expander downwardly with the member to expand the slips intogripping engagement with the casing to anchor the cage in the cr'zing,an upper packing element on the expander and engageable with the casingto seal the casing against the flow of fluid downwardly between the plugand the casing, a lower packing element carried by the cage andengageable with the casing to seal the casing against upward flow offluid between the plug and casing, said member having an internal valveseat a valve movably carried by the member and positioned for movementinto engagement with the seat to close the member against flow of fluidthrough the member and out of engagement with the seat to open themember, means in the member releasably engageable with the valve to holdthe valve in open position and releasable therefrom to permit movementof the valve into engagement with the seat and means carried by thevalve and engageable with the member upon closing of the valve to retainthe valve in closed position.

4. A bridging plug for wells comprising, a tubular member, couplingmeans releasably connecting the member to a string of pipe for movementwith the string and releasable by rotation of the string relative to themember, a slip cage around the member and slidable longitudinallyrelative thereto, casing-engaging slips carried by the cage and movableinto and out of engagement with a surrounding well casing, a slipexpander around the member and movable longitudinally of the cage toengage and expand the slips, releasable means connecting the cage to themember for movement therewith, said member being rotatable in the cageto release said connecting means and being movable downwardly in thecage when released therefrom, means on the cage frictionally engageablewith the casing to hold the cage stationary in the casing during suchrotation and downward movement of the member, means on the memberengageable with the slip expander to move the expander downwardly withthe member to expand the slips into gripping engagement with the casingto anchor the cage in the casing, an upper packing element on theexpander and engageable with the casing to seal the casing against theflow of fluid downwardly between the plug and the casing, a lowerpacking element carried by the cage and engageable with the casing toseal the casing against upward flow of fluid between the plug and thecasing, said member having an internal valve seat a valve movablycarried by the member in position for movement into engagement with saidseat to close the member and out of engagement with the seat to open themember, resilient means carried by the member and positioned to coactwith the valve and member to urge the valve toward said seat, means onthe valve engageable with the member upon closing of the valve to retainthe valve in closing position and means carried by the coupling meansand engageable with said valve and coupling means upon opening movementof the valve to hold said valve in a position opening the member.

5. A bridging plug for wells comprising, a tubular memher, couplingmeans releasably connecting the member to a string of pipe for movementwith the string and releasable by rotation of the string relative to themember, a slip cage around the member and slidable longitudinallyrelative thereto, casing-engaging slips carried by the cage and movableinto and out of engagement with a surrounding well casing, a slipexpander around the member and movable longitudinally of the cage toengage and expand the slips, releasable means connecting the cage to themember for movement therewith, said member being rotatable in the cageto release said connecting means and being movable longitudinally in thecage in either direction when released therefrom, means on the cagefrictionally engageable with the casing to hold the cage stationary inthe casing during such rotation and longitudinal movement of the memberin the cage, means on the member engageable with the slip expander tomove the expander downwardly upon downward movement of the member in thecage to expand the slips into gripping engagement with the casing toanchor the cage in the casing, packing means carried by the cage andsealingly engageable with the casing, and means on the member engageablewith the cage upon upward movement of the member in the cage to hold themember against rotation in the cage during rotation of the string torelease said coupling means.

6. A bridging plug for wells comprising, a tubular member, couplingmeans releasably securing the member to a string of pipe for movementwith the string, a slip cage around the member and slidablelongitudinally relative thereto, casing-engaging slips carried by thecage and movable into and out of engagement with a surrounding wellcasing, a slip expander between the slips and tubular member and movablelongitudinally of the cage to engage and expand the slips, releasablemeans connecting the cage to the member for movement therewith, saidreleasable means being releasable upon rotation of the member in onedirection to allow the member to move longitudinally relative to thecage when released therefrom, means on the member engageable with theexpander to move the expander downwardly with the member to expand theslips into engagement with the well casing, packing means on theexpander and on the slip cage and sealingly engageable with the casingand locking means carried by the tubular member and engageable with theslip cage upon upward movement of the member to lock the member againstrotation in the cage, said coupling means being rotatable upon rotationof the string of pipe when the member is locked against rotation in thecage to release the coupling from the member, said member having aninternal valve seat a valve carried by the tubular member and moveableto a closed position in engagement with the seat to close the memberagainst flow of fluid through the member and to an open position out ofengagement with the seat to open the member, and means carried by thecoupling and engageable with the valve and coupling upon openingmovement of the valve to hold the valve in open position.

7. A bridging plug for wells comprising, a tubular member, meansreleasably securing the member to a string of pipe for movement with thestring, a slip cage around the member and slidable longitudinallyrelative thereto, casing-engaging slips carried by the cage and movableinto and out of engagement with a surrounding well casing, a'

slip expander between the slips and tubular member and movablelongitudinally of the cage to engage and expand the slips, releasablemeans connecting the cage to the member for movement therewith saidreleasable means being releasable upon rotation of the member to allowthe member to move downwardly longitudinally relative to the cage whenreleased therefrom, means on the member engageable with the expander tomove the expander downwardly with the member to expand the slips intoengagement with the casing, a downwardly opening cupshaped packingelement carried by the slip cage and sealingly engageable with thecasing, sleeve means carried by the tubular member and initiallyengageable over the packing element to hold the packing element out ofengagement with the casing, means on the member engageable with saidsleeve means upon downward movement of the member in the cage to movesaid sleeve means downwardly to release said packing element, saidtubular member having an internal valve seat, a valve movably carried bythe tubular member and movable to one position to engage the seat toclose the member against flow of fluid therethrough and to anotherposition out of engagement with the seat to open the members to permitsuch flow, and means carried by the valve and engageable with the memberand valve when the valve is closed to retain said valve in closedposition.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,080,736 Nixon et a1. May 18, 1937 2,187,482 Baker et al.Jan. 16, 1940 2,270,648 Church Jan. 20, 1942 2,343,075 Otis Feb. 29,1944 2,585,706 Ware Feb. 12, 1952

